SINOTRUK HOWO A7 / T7H Aftertreatment DCU AZ1034121020 (China V Air-Assisted SCR Control Unit, DCU-KP)

The DCU is the box that decides how much AdBlue goes into the exhaust. On SINOTRUK’s third-generation China V air-assisted SCR system it talks to the engine ECU over CAN, reads the exhaust temperature sensors, works out the dosing rate and then drives the metering valve and the air valve inside the urea pump. When it fails, the engine derates and the truck stops earning.

This listing is the **DCU only** — part number **AZ1034121020**. The photos are of the actual unit: the casting on the housing reads AZ1034121020, and the yellow label reads **型号 DCU-KP**, **硬件版本 KP20160725-AA**, **产品名称 第三代后处理DCU**. Read those three lines against your old unit before you order, because the same housing shape is used across several hardware revisions.

**Specifications**

– Part number: AZ1034121020
– Label model: DCU-KP (third-generation aftertreatment DCU)
– Hardware version on label: KP20160725-AA
– System: SINOTRUK China V air-assisted SCR (AdBlue / DEF)
– Application: HOWO A7 / T7H / T5G, Steyr, Sitrak C7H, Hania — confirm by part number
– Mounting: four rubber-isolated lugs, bolts straight onto the original bracket
– Connector: round multi-pin harness plug, keyed — it will only go on one way
– Housing: sealed die-cast body, painted black, MADE IN CHINA cast on the side
– Condition: new

**How to check it is the right DCU**

1. **Part number first.** AZ1034121020 must match the number in your parts book or on the old housing. Do not go by appearance — the housing is shared between revisions.
2. **Hardware version second.** Compare KP20160725-AA on the label with your old label. A different suffix is a different hardware build.
3. **Connector third.** Count the pins and check the keyway. A China IV DCU uses a square plug; the China V unit uses the round plug shown here.

If the label on your old unit is unreadable, send us a photo of the housing, the connector and the VIN, and we check it against the SINOTRUK list before you pay.

**What a failing DCU looks like**

1. **Derate / limp mode.** The engine drops to reduced torque a few minutes after start, often with no obvious mechanical fault.
2. **MIL on with a NOx or SCR efficiency code.** The system stops dosing because it no longer trusts its own readings.
3. **No dosing at all.** The pump never runs its prime cycle at key-on, or runs constantly and never builds pressure — the DCU output stage has failed.
4. **CAN communication codes.** U-codes against the aftertreatment node, or the diagnostic tool cannot see the DCU at all.
5. **Intermittent faults over bumps.** Cracked solder joints and water ingress in the connector show up as faults that come and go.

Before condemning the DCU, check the simple things: battery voltage and earths, the harness plug for corrosion or pushed-back pins, the NOx sensors and the pump. A large share of “dead DCU” reports turn out to be a chafed loom or a wet connector.

**Fitting notes**

1. Ignition off, battery isolated, then wait for the system to finish its purge cycle before unplugging anything.
2. Release the connector latch — never lever on the housing.
3. Transfer the mounting rubbers if your bracket uses them; a rigid-mounted DCU fails from vibration.
4. Check the harness plug for green corrosion and water tracks. If the seal is perished, replace the plug, or the new unit will fail the same way.
5. After fitting, clear the old codes, run a forced dosing test and confirm the pump builds pressure before releasing the truck.

**Matching parts**

The pump that pairs with this DCU is the China V non-heated air-assisted urea pump **WG1034131181/1** — we list it separately. If you are replacing both, order them together so the hardware and software revisions match; a mismatched pair will dose incorrectly and log faults.

The dosing side this DCU controls — the urea nozzle **AZ932555200008/1** with its matched urea level and temperature sensor — is listed as one set [here](/product/sinotruk-urea-nozzle-az932555200008/).

**Ordering**

Minimum order 1 piece. Stock leaves within 2-3 working days, with photos of the actual unit and the packing before shipment, then the tracking number. Tell us the VIN if you want us to cross-check the revision first.

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